To be honest, I don't see a bit of difference between the cooling mechanics of a window A/C and a refridgerator. They use exactly the same principals and parts. Compressor, heat exhange coils, fan. Venting an AC into the larger living area is about the same as using a freezer/fridge. That is, given about equal efficiencies, set temps, and conditioned square footage, neither one puts more heat out than the other. I think a window A/C or split system has the advantage of having a nice powerful fan to keep the air moving well. Hmm, the one difference would be that a window AC collects condensate in the lower pan and tries draining it out the back. You could have freezing in the winter if you didn't insulate this path and divert the water into a collection system inside.

Here are some considerations from my perspective as a part-time Home Inspector:

1. A window unit A/C is very ineffcient when compared to a refridgeration unit.

2. When the temp. at the condenser coils goes below 65*F the pressure on the high side of the compressor gets high enough that it can damage the unit. For this reason I don't test A/C units when the outside air temp drops below 65*F.

3. The best you can reasonably hope for with a window A/C unit is a 20-30*F temp. reduction from the surrounding outside air temp. So 85*F outside air yields an average of 65-55*F cold air output. So in order to do the job properly you'd need a commercial refrideration unit for most installations.

4. With a 7' or 8' ceiling you are most likely cooling a lot of unused area.

Bottom line is a converted refridgerator or freezer will cost a lot less to purchase and operate especially if you buy a used one.

Of course if time, money and wasted space are of little or no concern then a walk-in fridge is high in gee whiz value.

I wonder why it works for some people like Jamil. Maybe their outside temps are more moderate like in the 70's. His site says his original unit crapped out after 6 years. Sounds pretty reasonable to me.

If I wanted to creat a 3' wide x 6' long x 8' tall walk-in fridge room, and needed to vent it to an inside room (just like a fridge, actually replacing the fridge. Any ideas? Don't think it would take much of a cooling unit. Was actually thinking of just ripping the guts out of the existing fridge and re-using them...

we are currently building a walk in cooler. I have read and some have suggested that we use a AC window unit, however a window unit will freeze if it runs to long, especially when you want temps of 40 or lower. so the solution we may be trying is using a 1.5 ton or 2 ton furnace with an outside AC condensing unit. If you use a unit big enough like this, it will defrost on its own during cooling cycles. All you would need is a freezer thermostat or a thermostat that will go down to 40 F. We do HVAC so we have one laying around so its cheaper for us. If your trying to stay cheap look on ebay or ask neighbors for used and good working units, dont buy a new one unless your going to use it ALOT! If you do decide to go with a window unit you will need to get a different thermostat along with a timing switch. The timing switch will shut of the condensor inside the unit, that way the freon wont be circulating and freezing up the pipes. With the condensor shut down, the fan will defrost the coils until the thermostat calls for cool air again.

I built a walk in frementation room(12x6x8), and got it up and running last weekend. It works fine for holding 68, and I've got it down to 58 with a 5500 btu window AC, but I don't think holding those low temps would be feasible for long term, but it can hold 68 just fine, and I have two fermentation cabinets to hold lower temps.

When I was building it though, I saw quite a few deals on Craig's list for commercial walkin coolers for under 1k.

I'm actually up near Sacramento. It gets as high as 110F in the summer and will dip below freezing a few days in winter.

I had an A/C guy living down the street from me and he told me it wouldn't work. He cited the same thing about high pressure and how it couldn't cool once it dipped below a certain temperature. He said it would be broken within a week. I know these A/C guys certainly know their stuff and have far more experience than me, but my experience tells me that you can get away with it and it will work. I measured air coming out of the unit at -7F. I froze 5%+ alcohol beer solid and this was in the middle of summer, about a 95F day.

I think the main reason the first unit died on me is that it got short cycled way too many times. I switched to a Johnson digital controller with an anti short cycle setting and that seems much gentler on the compressor.

I think if you need LOTS of cold storage it is more cost effective than the same space using refrigerators. Especially if the fridges are older and you insulate your walk-in very well.

__________________
I hope my post helped in some small way. If you need to contact me, please use email since it sometimes takes me several days to get back to the forum.

I have 6 foot long, 3 1/2 foot wide, 5 1/2 feet tall walk in. It is chilled with a tiny wall A/C unit that vents into my basement. I then run six beer lines about 35 feet, behind a wall, under my bar and up into a coffin box sitting on my bar.